In order to impart various properties to a polymer composition such as a resin and a rubber, calcium carbonate has been added to such a polymer. When calcium carbonate is added in order to improve the properties such as the strength of a polymer composition, a fine calcium carbonate, for example, having a BET specific surface area of about 10 to 40 m2/g may be used.
For example, Patent Document 1 discloses adding a calcium carbonate that is surface treated with a fatty acid salt and has a BET specific surface area of 10 m2/g or more to a resin or the like.
However, a calcium carbonate having a smaller particle size easily flies and thus is difficult to be handled. A calcium carbonate surface treated with, for example, a fatty acid also has a problem of easily flying.